The present invention relates generally to data-storage cartridges for storing digital information. More particularly, the invention relates to a data-storage cartridge having surface recesses formed therein to enhance the circulation of air within the cartridge.
FIG. 1 is a cross-sectional illustration of a conventional data-storage cartridge 100. The data-storage cartridge 100 comprises an outer shell 101 having an upper half 102 and a lower half 103. The data-storage cartridge 100 also includes a circular data-storage medium 104. The data-storage medium 104 is rotatably disposed within the outer shell 101. The data-storage medium has an upper recording surface 104a, a lower surface recording 104b, and an outer edge 104c. The data-storage medium 104 also includes a centrally-disposed hub 106. The hub 106 includes an upper surface 106a and a lower surface 106b. A fabric liner 110 is disposed on an inner surface 102a of the outer shell upper half 102. A fabric liner 111 is likewise disposed on an inner surface 103a of the outer shell lower half 103.
The lower half 103 of the outer shell 101 includes a hub access opening 107. A portion of the hub 106 is rotatably disposed within the hub access opening 107. The hub 106 and the hub access opening 107 are sized so that a gap 108 exists between the hub 106 and the hub access opening 107. This arrangement allows the hub 106 to freely rotate within the hub access opening 107. The hub 106 is adapted to engage a spindle of a disk drive (not shown) when the data-storage cartridge 100 is inserted into the disk drive. The spindle is coupled to a spindle motor within the disk drive. The spindle motor rotates the data-storage medium 104 via the spindle and the hub 106.
The outer shell 101 also includes a head access opening 109. The head access opening 109 permits the read/write heads of the disk drive to access to the data-storage medium 104. A spring-loaded shutter (not shown) covers the head access opening 109 when the data-storage cartridge 100 is not inserted in the disk drive.
The rotational motion of the data-storage medium 104 induces various airflow patterns within the data-storage cartridge 100. In particular, the air in contact with the rotating data-storage medium 104 flows radially outward, i.e., toward the outer edge 104c of the medium 104. This airflow is induced by the combined effect of the rotational motion of the data-storage medium 104 and viscous forces between the medium 104 and the surrounding air. (The airflow patterns within the data-storage cartridge 100 are represented by various arrows 112 shown throughout FIG. 1.)
The outward displacement of air along the lower surface 104b of the data-storage medium 104 causes air to be drawn into the data-storage cartridge 100 through the gap 108 (see the arrows 112). Hence, the air that is outwardly displaced along the lower surface 104b is replaced by air drawn through the gap 108. A substantial portion of the outwardly-displaced air eventually exits the data-storage cartridge 100 by way of the head access opening 109 after reaching the outer edge 104c of the data-storage medium 104.
The upper half 102 of the outer shell 101, by contrast, does not include any openings that allow a substantial volume of ambient air to enter the data-storage cartridge 100. The lack of such openings, in conjunction with the outward displacement of air along the upper surface 104a of the data-storage medium 104, causes a pressure differential to develop between the top and the bottom of the data-storage medium 104. In particular, the aerodynamic pressure above the upper surfaces 104a and 106a decreases in relation to the aerodynamic pressure below the lower surfaces 104b and 106b. The resulting pressure differential across the medium 104 is greatest proximate the hub 106, and decreases with increasing radial distance from the hub 106. The pressure differential is related to the rotational velocity of the data-storage medium 104. Specifically, higher rotational velocities increase the magnitude of the pressure differential.
The pressure differential across the data-storage medium 104 can produce a number of undesirable effects. For example, the pressure differential tends to lift the data-storage medium 104 upward, i.e., in the z+ direction (the z+ direction is denoted on a coordinate system 8 shown in FIG. 1). This upward displacement can result in inadvertent contact between the medium upper surface 104a and a flying read/write head positioned proximate the upper surface 104a during data storage and retrieval operations. Furthermore, the upward displacement of the medium 104 can increase the mechanical loading of a non-flying read/write head beyond acceptable levels. Inadvertent head-medium contact and high mechanical loading can result in damage and premature wear of the read/write head and the data-storage medium 104. These factors can also lead to a loss of data from the data-storage medium 104.
In addition, the vertical displacement of the data-storage medium 104 can make it difficult to load the read/write head onto the data-storage medium 104. In particular, substantial vertical displacement of the data-storage medium 104 can cause the read/write head and its supporting structure to contact the data-storage medium 104 as the read/write head is moved from its parked position beside the medium 104. Such contact can damage the data-storage medium 104, the read/write head, and the supporting structure of the read/write head. Furthermore, the need to account for the vertical displacement of the data-storage medium 104 may cause the height (z dimension) of the data-storage cartridge 104 to be greater than would otherwise be required. The need to account for this displacement can also cause the height of the disk drive in which the cartridge 104 is utilized to be greater than would otherwise be required.
In addition, low rates of airflow over the upper surface 104a of the medium 104 can result in oscillations in the medium 104. More particularly, low airflow rates across the surface 104a exert minimal aerodynamic damping on the data-storage medium 104. Minimal damping increases the potential for the data-storage medium 104 to oscillate. Oscillation of the medium 104 can result in the problems and disadvantages described above in connection with the vertical displacement of the data-storage medium 104. Furthermore, low rates of airflow over the upper surface 104a may cause a read/write head positioned above the upper surface 104a to operate at unacceptably high temperatures.
The above discussion illustrates the existing need for a data-storage cartridge having a data-storage medium that operates with a minimal aerodynamic pressure differential across its upper and lower surfaces. Optimally, the cartridge should operate with sufficient airflow across its upper surface to inhibit substantial oscillation of the medium, and to adequately cool a read/write head positioned above the upper surface. The present invention is directed to these and other objects.
In accordance with the above-noted objects, a presently-preferred embodiment of the invention comprises a data-storage cartridge having an outer shell. The outer shell includes an upper half having an inner surface. A recess is formed in the inner surface. The recess extends between a first position proximate an outer periphery of the inner surface and a second position proximate a center of the inner surface. The outer shell also includes a lower half. A hub access opening is formed in the lower half of the outer shell. The hub access opening is substantially aligned with the center of the inner surface.
The data-storage cartridge also comprises a data-storage medium. The data-storage medium has a centrally-disposed hub and an outer edge. The data-storage medium is rotatably disposed within the outer shell so that at least a portion of the hub is positioned within the hub access opening and at least a portion of the outer edge is positioned proximate the outer periphery of the inner surface.
The data-storage cartridge further comprises a liner positioned along the outer shell inner surface so that the liner covers a portion of the recess between the first and the second ends of the recess. The liner and the recess thereby form a passage for directing air toward the hub of the data-storage medium in response to rotation of the data-storage medium. Directing air toward the hub of the data-storage medium in this manner minimizes a difference in aerodynamic pressure across the data-storage medium.
Further in accordance with the above-noted objects, another presently-preferred embodiment of the invention comprises a data-storage cartridge having a rotatable data-storage medium. The data-storage medium includes a centrally-disposed hub and an outer peripheral edge. The data-storage cartridge also comprises an outer shell that encloses at least a portion of the data-storage medium. The outer shell has an inner surface that faces toward the data-storage medium. A recess is formed in the inner surface. The recess has a first end and a second end. The first end is located proximate the outer peripheral edge of the data-storage medium and the second end is located proximate the hub of the data-storage medium in one particular preferred embodiment of the invention.
The data-storage cartridge also includes a liner attached to the inner surface of the outer shell so that the liner covers a portion of the recess between the first and the second ends of the recess. The recess and the liner thereby form a passage for directing air therethrough in response to rotation of the data-storage medium.
Further in accordance with the above-noted objects, another presently-preferred embodiment of the invention comprises a data-storage cartridge having a data-storage medium that is rotatable about a center hub. The data-storage cartridge also includes an outer shell having an inner surface. The outer shell encloses the data-storage medium so that at least a portion of the inner surface is positioned above the data-storage medium. A recess is formed in the inner surface. The recess extends between a first position and a second position. The first position is located proximate an outer edge of the inner surface and the second position is located proximate a center of the inner surface in one particular preferred embodiment of the invention.
The data-storage cartridge also includes an airflow barrier. The airflow barrier covers a portion of the recess between the first and the second positions so that the airflow barrier and the recess form a passage extending between the first and the second positions. The passage circulates air toward the hub of the data-storage medium in response to rotation of the data-storage medium.
Further in accordance with the above-noted objects, a preferred method for minimizing a pressure differential across a data-storage medium within a data-storage cartridge comprises the step of rotating the data-storage medium and thereby causing air to flow toward an outer peripheral edge of the data-storage medium. The method further comprises the step of circulating the air away from the outer peripheral edge of the data-storage medium by way of a passage formed in an outer shell of the data-storage cartridge. The method also includes the step of discharging the air from the passage proximate a center hub of the data-storage medium.